News Column

"Storage Device with Reflection Compensation Circuitry" in Patent Application Approval Process

September 2, 2014

By a News Reporter-Staff News Editor at Information Technology Newsweekly -- A patent application by the inventors Livshitz, Boris (Eagan, MN); Hoque, Anamul (Lakeville, MN); Rabe, Cameron C. (Inver Grove Heights, MN); Gleason, Jeffrey A. (Burnsville, MN), filed on February 8, 2013, was made available online on August 21, 2014, according to news reporting originating from Washington, D.C., by VerticalNews correspondents.

This patent application is assigned to LSI Corporation.

The following quote was obtained by the news editors from the background information supplied by the inventors: "Disk-based storage devices such as hard disk drives (HDDs) are commonly used to provide non-volatile data storage in a wide variety of different types of data processing systems.

"In a typical HDD, data is recorded on tracks of a magnetic storage disk using a write signal comprising multiple write pulses. The write signal is generated by a write driver that is coupled to a write head of the HDD via a transmission line. In order to record a given data bit, the write driver generates a write pulse that transitions from a negative write current to a positive write current, or vice-versa.

"However, writing data to the storage disk can be challenging when utilizing conventional write pulses, particularly at high data rates on the order of 1 Gigabit per second (Gb/s) or more. For example, impedance mismatches between the write driver, the transmission line and the write head often cause write pulse reflections that distort the desired shape of the write pulse waveform at the write head. Such impedance mismatches become significantly more pronounced at high data rates, and can adversely impact on-track recording performance in terms of recorded data fidelity as well as off-track recording performance due to issues such as adjacent track erasure and far track erasure. Similar problems can arise when writing data to other types of storage media."

In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventors' summary information for this patent application: "In one embodiment, an HDD or other storage device comprises a storage medium, a write head configured to write data to the storage medium, and control circuitry coupled to the write head. The control circuitry comprises a write driver configured to generate a write signal comprising a write pulse, and reflection compensation circuitry coupled to or otherwise associated with the write driver and configured to provide one or more reflection compensation pulses in the write pulse.

"By way of example only, the reflection compensation circuitry may be configured to generate a given one of the reflection compensation pulses as a negative-going current pulse having a substantially zero steady-state current. The reflection compensation circuitry may be further configured to superimpose the given reflection compensation pulse on the write pulse by combining the negative-going current pulse having the substantially zero steady-state current with a positive steady-state write current of the write pulse so as to produce a modified write pulse having the negative-going current pulse superimposed on the positive steady-state write current.

"Other embodiments of the invention include but are not limited to methods, apparatus, systems, processing devices, integrated circuits and computer-readable storage media having computer program code embodied therein.


"FIG. 1 shows a perspective view of a disk-based storage device in accordance with an illustrative embodiment of the invention.

"FIG. 2 shows a plan view of a storage disk in the storage device of FIG. 1.

"FIG. 3 is a block diagram of a portion of the storage device of FIG. 1 including a preamplifier comprising multiple write drivers and associated reflection compensation circuitry.

"FIG. 4 shows an example of a write signal comprising a write pulse without a superimposed reflection compensation pulse.

"FIG. 5 shows an example of a write signal comprising a write pulse with a superimposed reflection compensation pulse.

"FIGS. 6A, 6B and 6C illustrate the operation of a portion of the reflection compensation circuitry associated with a given write driver of FIG. 3.

"FIG. 7 illustrates interconnection of the storage device of FIG. 1 with a host processing device in a data processing system.

"FIG. 8 shows a virtual storage system incorporating a plurality of disk-based storage devices of the type shown in FIG. 1."

URL and more information on this patent application, see: Livshitz, Boris; Hoque, Anamul; Rabe, Cameron C.; Gleason, Jeffrey A. Storage Device with Reflection Compensation Circuitry. Filed February 8, 2013 and posted August 21, 2014. Patent URL:

Keywords for this news article include: LSI Corporation, Information Technology, Information and Data Processing.

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Source: Information Technology Newsweekly

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